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A method for preparing high-quality silicon carbide from crystalline silicon cutting waste

A technology for cutting waste and crystalline silicon, which is applied in chemical instruments and methods, carbon compounds, inorganic chemistry, etc., can solve the problems of product quality impact, increased production cost, and high requirements for reaction equipment, so as to increase the mutual contact area, reduce oxidation, Guaranteed the effect of reductive conditions

Active Publication Date: 2019-09-27
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This kind of silicon carbide obtained by acid leaching treatment will still introduce some impurities in the later stage when the carbon source is added, which will affect the quality of the product.
Secondly, protective gas needs to be introduced into the reaction system, and the requirements for reaction equipment are relatively high, which increases the production cost

Method used

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  • A method for preparing high-quality silicon carbide from crystalline silicon cutting waste
  • A method for preparing high-quality silicon carbide from crystalline silicon cutting waste
  • A method for preparing high-quality silicon carbide from crystalline silicon cutting waste

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Weigh 67g of cutting waste, 23.8g of petroleum coke, 3g of sodium chloride, 2g of sodium fluoride, and 4.2g of polyacrylic alcohol, add 10g of water, mix evenly, and press pellets (pressing pressure is 40Mpa, holding time is 60s, pellets 30~40mm in diameter), put it in an induction furnace, spread 15mm graphite powder on top of the pellets, smelt at 1400~1500℃, after cooling, take out the silicon carbide crystal block and break it, use 10wt% hydrochloric acid and 5wt% hydrogen The mixed acid of hydrofluoric acid is purified by ultrasonic-assisted stirring and pickling (the pickling conditions are: ultrasonic frequency is 80kHz, stirring speed is 400rpm, pickling time is 2h), and the purity of silicon carbide powder obtained after drying is 98.8%, free The silicon content is 0.15% and the free iron content is 0.20%.

Embodiment 2

[0031] Weigh 67.47g of cutting waste, 20.53g of graphite powder, 10ml of 0.24g / ml sodium chloride and potassium chloride mixed solution (the mass ratio of sodium chloride and potassium chloride is 2:1) and 9.6g polyacrylamide, After uniform mixing, the pellets are pressed (compression pressure is 60Mpa, holding time is 30s, pellet diameter is 20-30mm), put into resistance furnace, spread 30mm graphite powder and petroleum coke on top of pellets at 1500~1600℃ After smelting, after cooling down, take out the silicon carbide crystal block and break it, and use the mixed acid of 20wt% hydrochloric acid and 15wt% sulfuric acid to carry out ultrasonic-assisted stirring and pickling purification (the pickling conditions are: ultrasonic frequency is 50kHz, stirring speed is 800rpm, acid The washing time is 0.25h), the purity of the silicon carbide powder obtained after drying is 96%, the free silicon content is 0.13%, and the free iron content is 0.19%.

Embodiment 3

[0033] Weigh 69.12g of cutting waste, 12.36g of activated carbon, 10.52g of graphite powder, 4g of polyacrylamide and 4g of polyacrylic alcohol, mix them evenly, and press the pellets (pressing pressure is 15Mpa, holding time is 120s, pellet diameter is 40~ 50mm), put into the Acheson furnace, spread 60mm graphite powder on top of the pellets, smelt at 1700~1800℃, after cooling down, take out the silicon carbide crystal block and break it, use 20wt% sulfuric acid and 5wt% hydrofluoric acid The mixed acid is purified by ultrasonic-assisted stirring and pickling (the pickling conditions are: the ultrasonic frequency is 150kHz, the stirring speed is 100rpm, and the pickling time is 4h). The purity of the silicon carbide powder obtained after drying is 96.8%, and the free silicon content It is 0.15% and the free iron content is 0.19%.

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Abstract

The invention belongs to the technical field of secondary resource utilization, and relates to a method for preparing high-quality silicon carbide through a crystalline silicon cutting waste material.The method solves the treatment problem of the crystalline silicon cutting waste material, and is characterized by comprising the steps of weighing and mixing the crystalline silicon cutting waste material, a carbon source and a purifying agent according to the proportion, pressing into pellets, drying, smelting at high temperature to prepare SiC crystalloid blocks, crushing, acid pickling and drying to obtain the high-quality silicon carbide powder. According to the method for preparing the high-quality silicon carbide through the crystalline silicon cutting waste material provided by the invention, not only is the utilization rate of the diamond wire cutting waste material high, the production cost is low, and the produced silicon carbide has high purity and good quality.

Description

Technical field [0001] The invention belongs to the technical field of secondary resource utilization, and relates to a method for preparing high-quality silicon carbide from crystalline silicon cutting waste. Background technique [0002] With the rapid development of the semiconductor industry and photovoltaic industry, the global demand for solar-grade silicon continues to grow. When preparing solar cells, it is necessary to cut crystalline silicon ingots into silicon wafers. The working principle of mortar cutting in the wire cutting method is water-based cutting mortar composed of silicon carbide particles as abrasive, polyethylene glycol as dispersant, and water as solvent. In, the metal ribbon moves the silicon carbide particles to cut the silicon rod. During this process, due to the small difference between the diameter of the cutting wire and the thickness of the required crystalline silicon wafer, as much as 50%-52% of the crystalline silicon will enter the cutting flu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B32/984
Inventor 邢鹏飞姜胜南崔晓华刘洋都兴红高波李大刚
Owner NORTHEASTERN UNIV LIAONING